Polyvinyl acetal resin sheets containing tributyrin



Patented Dec. 26, 1939 UNITED STATES POLYVINYL ACETAL RESIN SHEETSCONTAINING TRIBUTYRIN Bruce E. Gramkee, Rochester, N. r., assignor toEastman Kodak Company, Rochester, N. Y., a corporation of New Jersey NoDrawing. Application December 29, 1937, Serial No. 182,301

- and more particularly to compositions comprising a polyvinyl acetalresin and a conditioning agent.

One object of this invention is to produce compositions of matter whichmay be made into permanently transparent, strong and flexible sheets -orfilms of desired thinness which are substantially waterproof, areunaffected by ordinary photcgraphic fluids and possess the desiredproperties of a supportfor sensitive photographic coat-' ings. Anotherobject of my invention is to produce compositions of matter which can bemade into sheets suitable for use in laminated, shatter-proof, glass.Still another object is to produce compositions which can be rolled,extruded, molded or otherwise worked into relatively thick sheets andmassive plastics. A further object is to produce compositions suitablefor use in lacquers, artificial silk filaments, wrappin tissues and thelike. Other objects will hereinafter appear.

I have discovered that tributyrin, i. e., lycerol tributyrate, is a veryuseful conditioning agent for polyvinyl acetal resins. Not only does itserve as a .plasticizer in the accepted sense of the term, increasingthe flexibility and toughness of polyvinyl acetal resin films, sheets,or other objects or masses containing it, but when used in amounts ofabout 40 or or more parts per parts of the resin, it has an unusual andremarkable effect which I may call elasticizing. That is to say, asheet'of polyvinyl acetal resin containing about 40 or more parts oftributyrin per 100 parts of resin possesses the property which, in therubber industry, is known as "nerve: namely, the prop- "erty ofstretching to a considerable extent when tension is exerted upon it, andreturning to its original dimensions when the tension is released. Thisproperty renders such sheets, which I shall call rubbery sheets,particularly useful in the manufacture of shatter-proof glass.

For the manufacture of cast films or sheets,

the polyvinyl acetal resin and tributyrin may be or more of tributyrinper 100 parts of resin may be employed, depending upon the nature of theresin andthe purposefor which the sheets are to be used. Suitableproportions of tributyrin for anyresinandanypurposemaybereadilyde-PATENT OFFICE termined by experiment. For the manufacture of sheetssuitable for photographic, film base, from 3 to 25 parts of tributyrinper 100 parts of resin are suitable. The resin solution is cast asasheet, the solvent evaporated, and the sheet. I stripped from thecasting surface.

Sheets for use in laminated glass may be formed by casting, or may bemade without the use'of volatile solvent by extrusion, for example inthe manner set forth in application Serial No.. 10 147,934 of John S.Kimble and Ernest C. Blackard, filed June 12, 1937. For instance, 4001more parts of tributyrin and 100 parts of a polyvinyl acetal resin maybe mixed in a suitable, jacketed l mixer at a low temperature, forexample 10 C., and the mixture may then be worked on hot rolls, in themanner described in U. S. Patent 2,048,686 of F. R. Conklin, untilcomplete homogenization has'taken place. The mass thus producedmay'thenbe extruded through an annular die, and the tube so formed slitto form a sheet. When the resin used is a polyvinyl formaldehyde acetalresin, it will usually be found necessary to use 60 or more parts oftributyrin per 100 parts of resin.

The polyvinyl acetal resins can be prepared by reacting polyvinylalcohol with an aldehyde in the presence of an acetal condensationcatalyst, e. g., a mineral acid. These resins can also be prepared bysimultaneously de-esterifying a poly- 30 vinyl aliphatic ester andreacting the de-esterifl- Y cation product with an aldehyde in thepresence of a de-esterifying catalyst and acetal condensation catalyst.Mineral acids are catalysts for both de-esterification and acetalformation. Among 35 the polyvinyl acetal resins with which tributyrin isuseful may be mentioned, as illustrative examples, the polyvinylformaldehyde acetal resins, the polyvinyl acetaldehyde acetal resins,the polyvinyl formaldehyde acetaldehyde mixed acetal resins, thepolyvinyl butyraldehyde acetal resins, and the polyvinyl butyraldehydeacetaldebyde' mixed acetal resins.

Examples of the preparation of polyvinyl formaldehyde acetal resins maybe found in U. S. Patent 1,955,068, Examples 1, 4 and 5; in U. S. Patent2,036,092, Examples 1, 2, 3, 7 and 8; in British Patent 454,691,Examples 1, 2, 3, 4, 5, 6 and 7; in British Patent 404,279, Example 3;and in British Patent 436,072, Examples 1, 2, 3, 4, 5, 6 and 7. Furtherexamples of the preparation of polyvinyl formaldehyde acetal resins areas fol-. lows:

25 lbs. of polyvinyl acetate, the viscosity of whose "molar solution(86.08 g. per liter) in 55 benzene was 45 centipoises, was dissolved in75 lbs. of 70% acetic acid. To this solution were added 56 grams ofhydroxylamine hydrochloride, for stabilizing the resin, 5.25 lbs. oftrioxymethylene, and 6.25 lbs. of 35% HCl. The reaction mixture wasallowed to stand for 5 days at 40 0., after which it was diluted withacetic acid. The resin was precipitated bypouring into cold water,washed, and dried. Analysis showed the resin to have an acetate groupcontent equivalent to 10.6% by weight of polyvinyl acetate and ahydroxyl group content equivalent to 7.1% by weight of polyvinylalcohol. The stabilization of polyvinyl acetal resins by hydroxylamineis claimed 1 in the application of Joseph B. Hale, Serial No. 149,916,filed June 23, 1937, Patent No. 2,146,735. 70 lbs. of polyvinyl acetate,the viscosity of whose molar solution in benzene was 45 centipoises, wasdissolved in a mixture of 336 lbs. of go glacial acetic acid and 224lbs. of water. After solution was effected, there were added a solutionof 318 grams of sodium nitrite in 500 cc. of water, for stabilizing theresin, 15.2 lbs. of trioxymethylene and 17.5 lbs. of 85% HCl. The :5reaction mixture was allowed to stand for 5 days at 40 C., whereupon 5lbs. additional 35% HCl was added and the reaction mixture was thendiluted with a mixture of acetic acid and ethyl alcohol, and the resinwas precipitated by pourao ing ,into cold water, washed, and dried.Analysis showed the resin to have an acetate group con-' tent equivalentto 10.7% by weight of polyvinyl acetate and a hydroxyl group contentequivalent to 11.2% by weight of polyvinyl alcohol. The a stabilizationof polyvinyl acetal resins by nitrous acid is claimed in the applicationof Charles R. Fordyce and Marttl Salo, Serial No. 159,193, filed August14, 1937, Patent No. 2,159,263.

Examples of the preparation of polyvinyl acetaldehyde acetal resins maybe found in U.'S. Patent 2,044,730, Example 1; U. S. Patent 1,955,068,Example 2; U. S. Patent 2,036,092, Examples 4, 5 and 6; British Patent466,598, Examples 1, 2, 3, 4 and 7; British Patent 404,279, Examples l,2, 4, 5, 6, 7 and 8; U. S. Patent 1,990,399; and French Patent 808,578,Examples 1, 2 and 3.

Additional examples of the preparation of polyvinyl acetaldehyde acetalresins are as folows:

100 lbs. of polyvinyl acetate, the viscosity of whose molar solution inbenzene was 45 centipoises, was dissolved in 300 lbs. of 95% ethylalcohol. To this solution were added lbs. of paraldehyde and 25 lbs. ofI101. The reaction mixture was allowed to stand for 4 days at 0., afterwhich it was diluted with ethyl alcohol, and the resin-precipitated bypouring into cold water, washed and dried. Analysis showed the resin tohave an acetate group content equivalent to 2.1% by weight of polyvinylacetate and a hydroxyl group content equivalent to 12.9% by weight ofpolyvinyl alcohol.

25 lbs. of polyvinyl acetate, the viscosity of whose molar solution inbenzene was centipoises, was dissolved in lbs. of ethyl alcohol. To thissolution was added 8 lbs. of paraldehyde and a solution of 3 lbs. 12ozs. ofsulfuric acid in 3 lbs. 12 ozs. of 95% ethyl alcohol. Thereaction mixture was allowed to stand for 7 days at 40 C., after whichit-was diluted with ethyl alcohol, and the resinf-pre p by p r n intocold water, washed, and dried. Analysis showed the resin to have anacetate group con-' 1 tent equivalent to 1.7% by weight of polyvinylacetate and a hydroxyl group content equivalent to 13.8% by weight ofpolyvinyl alcohol.

Examples of the preparation of polyvinyl formaldehyde acetaldehyde mixedacetal resins may be found in British Patent 430,136, Examples 1, 2, 3,4, 5 and 6; British Patent 445,565, Example 2; British Patent 465,873,Examples 1, 2, 3, 4, 5 and 6; French Patent 808,586, Examples 1, 2, 3,4, 5, 6, 12, 13, 14, 15, 16, 17, 18 and 19.

Additional examples of the preparation of polyvinyl formaldehydeacetaldehyde mixed acetal resins are given in the application of RalphH. Talbot, Serial No. 85,960, filed June 18, 1936, as follows: Y

"Example 1 parts (1.16 mol. .calculatedas' monomeric vinyl acetate) of apolyvinyl acetate (45 centipoises), 100 parts of ethyl alcohol, parts ofethyl acetate, 34 parts (.77 mol. as monomeric acetaldehyde) ofparacetaldehyde and 5.8 parts (.196 mol. as monomeric formaldehyde) ofparaformaldehyde were placed in an enamelled .vessel and brought intosolution by stirring. When solution was complete, 10 parts of sulfuricacid (sp. g. 1.84) in 10 parts of water were added, and the mixturestirred. The mixture was maintained at a temperature of 40 C. for 144hours. The contents of the vessel were then diluted with about two and ahalf volumes of acetone, and the mixture precipitated into water. Theprecipitated resin was washed free from impurities by repeated changesof cold water, and dried. The resin, when analyzed, gave a hydroxylgroup content equivalent to about 6.4 per cent by weight of po yvinylalcohol, an acetate group content equivalent to about 4.0 per cent byweight of polyvinyl acetate, a formaldehyde acetal group contentequivalent to about 15.9 per cent by weight of polyvinyl formaldehydeacetal and an acetaldehyde acetal group content equivalent to about 73.9per cent by weight of polyvinyl acetaldehyde acetal. The polyvinylacetal portion of the resin was therefore made up of about 19.7 per centby moles of polyvinyl formaldehyde acetal and about 80.3 per cent bymoles of polyvinyl acetaldehyde acetal. The resin was soluble in acetoneto an extent which permitted coating a film or sheet from the resin.

Example 2 '50 parts (.58 mol. as monomer) of polyvinyl acetate (45centipoises), 50 parts of ethyl alcohol, 90 parts of ethyl acetate, 17parts (.385 mol.

as monomeryof paracetaldehyde, 2.9 parts (.098

mol. as monomer) of paraformaldehyde, 5 parts of-sulfuric acid and 5parts of water were treated as in Example 1 for 161 hours. The wellwashed and dried resin gave upon analysis a hydroxyl group contentequivalent to about 9.6% by weight of polyvinyl alcohol, an acetategroup content equivalent to about 4.1% by weight of polyvinyl acetate, aformaldehyde acetal group content equivalent to about 13.9 per cent byweight of polyvinyl formaldehyde acetal, and an acetaldehyde acetalgroup content equivalent to about 69.9'per cent of polyvinylacetaldehyde acetal. The polyvinyl acetal portion of the resin wastherefore made up of about 18.5 per cent by moles of polyvinylformaldehyde acetal and 81.5 per cent by moles of polyvinyl acetaldehydeacetal. The resin was soluble in acetone to an extent which permittedcoating a film or sheet from the resin.-

vinyl acetate (45 centipoises) 1700 parts of ethyl acetate, 2250 partsof ethyl alcohol (95%) and 48 parts (1.57 mol. as monomer) ofparaformaldehyde (trioxymethylene) were placed in a vessel equipped witha reflux condenser and a means of agitation, and the contents brought toa temperature of about 70C. by means of steam heating. "-182.25 partsofsulfuric acid (sp. .g. 1.84) dissolved in 51.5 parts of water wereadded, and

the whole was heated at about 70 C. for about five hours, agitatingthroughout. At this'point, 266.4 parts (6.05 mol. as monomer) ofparacetaldehyde were added and heating atLabout 70 C.

with agitation was continued fora further period of twenty hours. Thecontents ofthe reaction vessel were neutralized with ammonium hydroxideand diluted with water precipitating the resin The ,cake was cut intosmall pieces resin was free from solvents, salts and other impurities.The resin, upon analysis, showed a hydroxyl group content equivalent toabout 10.1 per cent by weight of polyvinyl alcohol, an acetate groupcontent equivalent to about 3.2 per cent by weight of polyvinyl acetate,the remainder of the weight of the resin being polyvinyl acetal. Thepolyvinyl acetal portion of the resin was made up of about.80 per centby moles I of polyvinyl acetaldehyde acetaland about 20 per cent bymoles of polyvinyl formaldehyde acetal. The resin wasnot quite solublein acetone, but could be made to dissolve by admixing small amounts ofother solvents, such as alcohols, with the acetone."

Examples of the preparation of polyvinyl butyraldehyde acetal resins maybe ,found in U. 8. Patent 2,044,730, Examples 2, 5 and 6; British Patent466,598, Example 5; French Patent 813,303, Example 1; French Patent813,514, Examples 1, 2, 3 and 4; and, British Patent 459,878, Examples1, 2, 5, 6, 7, 8, 9 and 10.

Additional examples of the preparation of polyvinyl butyraldehyde acetalresins are as follows:

20 lbs. of polyvinyl acetate, the viscosity of 7 whose molar solution inbenzene was 45 centipoises. was dissolved in 20 lbs. of ethyl 'al-.-

cohol and 36 lbs. of .ethyl acetate. To this solution was added 13 lbs.of butyraldehyde and a solution of 2 lbs. ofsuhurlcacid in 2 lbs. of Ywater.

diluted with acetone, and the resin precipitated by pouring into coldwater, washed and dried. Analysis showed theresin to have an acetategroup content equivalent to 7.8% by weight of polyvinyl acetate and ahydroxyl group content equivalent to 4.8% by weight of polyvinylalcohol.

23.6 lbs. of polyvinyl acetate, the viscosity of whosemolar solution inbenzene was 45 centipoises, was dissolved in 56.5 lbs. of 95% ethylalcohol. To this solution was added 7.9 lbs. of butyraldehyde and 5.9lbs. of 35% HCl. The

reaction mixture was allowed to stand for 4 days at 40 C-., after whichit was diluted with ethyl alcohol and acetic acid, and the resinprecipitated by pouring into cold water, washed, and dried. Analysisshowed the'resin to have an acetate group content equivalent to 3.1% byweight of polyvinyl acetate and a hydroxyl group content equivalent to16.3% by weight of polyvinyl alcohol,

An example of thepreparation of a polyvinyl butyraldehyde acetaldehydemixed acetal resin is given in French Patent 813,303, Example 2.

What I claim as my invention and desire to be secured by Letters Patentof. the United States is: r

1. A transparent, rubbery sheet comprising parts of a polyvinyl acetalresin and at least The reaction mixture was allowed tov stand for 8 daysat 40 C., after which it was- 40 parts, approximately, of tributyrin asan 3. A transparent, rubbery sheet comprising.

100 parts of a polyvinyl formaldehyde acetal resin and at least 60parts, approximately, of tributyrin as an elasticlzer therefor.

4. A transparent, rubbery sheet comprising 100 parts of a polyvinylbutyraldehyde acetal resin and at least 40 parts, approximately, oftributyrin as an elastlcizer'therefor.

5. A transparent, rubbery sheet comprising a polyvinyl acetal resin andan amount of tributyrin sumcient to impart to the sheet a rubberycharacter without substantially impairing its transparency.

Bauer: E. GRAMKEE;

